Obviously, Americans are too lazy to convert, since there's really no reason to not use metric once the switch is done. I admit that everything being so nicely organized is something I really only started to appreciate when I took my first physics class. When you're a common person who only works with length, volume, time, temperature and weight measurements, it's easy to keep track of the imperial system for your own use (and of those, temperature only has one unit per system, and time is the same in both systems). Throw in energy in various forms, force, pressure, electrical resistance, charge, etc. all with conversion factors pulled out of a monkey's ass and anyone would get confused. I don't even know the imperial units for any of those except force is pounds.
As for weird conversions, you get used to it. Sure a mile is 5280 feet because...uh...shit? But people are familiar with how big a foot is, and how big a mile is, and have enough sense to use a number of units someone can work with easily (ex. that house is 7 miles away, instead of saying 36960 feet to force someone to convert to miles to accurately imagine it). So most of the time, I don't care that a mile is some weird number of feet, because I just don't need to work with both units in any situation. Or if I do, I approximate with 5000 and it's not a big deal.